Understanding The Light Spectrum

What Is The Light Spectrum And Why Is It Important For LED Lighting?

The light spectrum refers to the range of wavelengths of light that a light source emits, including both visible and non-visible light.

Understanding this is essential when choosing lighting for tasks, environments, or applications where colour accuracy, brightness, or plant growth matters.

What Is The Visible Light Spectrum?

The human eye sees light in the range of approximately 380–780 nanometres (nm). Here's a basic breakdown:

Violet: 380–450nm
Blue: 450–495nm
Green: 495–570nm
Yellow: 570–590nm
Orange: 590–620nm
Red: 620–780nm

LEDs can be tuned to emit specific parts of this spectrum depending on the desired application.

What Is A Spectral Power Distribution (SPD) Chart?

An SPD chart shows how much light an LED emits at each wavelength. It helps you see the colour makeup of the light and is useful for comparing:

CRI (Colour Rendering Index) – how accurately colours appear under the light
CCT (Correlated Colour Temperature) – how “warm” (yellow) or “cool” (blue) the light appears
PAR (Photosynthetically Active Radiation) – for horticultural applications

Most Ultra LEDs products include SPD charts or light spectrum data in their technical datasheets, available for download on each product page.

How To Access Spectrum Data for Ultra LEDs Products

You can view or download spectrum data in our product datasheets, which include:

SPD charts
CRI and CCT values
Beam angles and efficiency

Just visit the specific product page on our website and look for the “Downloads” section.

If you need help interpreting the data or choosing a product based on light spectrum performance (e.g., for photography, retail, or plant growth), feel free to contact our technical support team.

Author: Tom Cain, Technical Manager @ Ultra LEDs

Tom brings years of hands-on experience in professional LED lighting solutions, specialising in product development, system integration, and lighting control technologies. As Technical Manager at Ultra LEDs, he supports the team with in-depth knowledge across LED drivers, dimming protocols, and complex installations. His expert insights help ensure our content is accurate, relevant, and grounded in real-world applications.

Get in touch with Ultra LEDs today

From high-CRI strip to RGBW tape and horticultural lighting, our full range includes spectrum-tested solutions with downloadable SPD data. Explore the range or speak to our team for specification advice.